Apparatus for desalinating water

ABSTRACT

An apparatus and method for removing contaminants from water having solid contaminants dissolved therein. Contaminated water flows across a grid and into a storage tank. The grid utilizes solar energy to heat that water to a predetermined temperature. A heat transfer structure which is dome-shaped and receives water from the storage tank and a preheater means utilizing solar energy heats the water to a further predetermined temperature. An evaporator means receives the heated water and exposes it to a vacuum condition so that the temperature of the water is above the saturation temperature. The water is thus vaporized, and solid contaminants dissolved therein are separated therefrom. The solids are deposited on a plurality of moving belts and are then moved into a solids removal system. The solids removal system comprises a plurality of trap door pairs upon which the solids are deposited and which are sequentially opened so that the vacuum conditions existing in the evaporator are not disturbed. Vapor transferring means removes the water vapor from the evaporator and transfers it to the heat transfer structure wherein it is condensed to form distillate which is free of solid contaminants. Distillate removal means then removes the distillate from the heat transfer structure to collection or usage means.

This is a division, of application Ser. No. 625,850, filed Oct. 28, 1975now U.S. Pat. No. 4,118,283, Oct. 3, 1978.

BACKGROUND OF THE INVENTION

The present invention relates to desalination, and, more particularly,to an apparatus and a method utilizing solar energy in the desalinationprocess.

Distillation devices are used to purify volatile substances, and havefound application in the chemical and petroleum industries. Recently,such devices have been used in desalination processes wherein salts areprecipitated out of saline water to produce pure water. Recently, therehas been an interest in applying distillation processes to desalinatinglarge quantities of water. This interest has been sharpened due todroughts in vast land areas which are, however, located near greatbodies of salt water. An apparatus and a process which efficientlydesalinates large amounts of water could find wide applications in suchdrought ridden areas, as well as in densely populated areas which, atpresent, appear to have adequate water supplies.

Most known distillation devices suffer a common drawback ofinefficiency, and hence are not suitable for use in such large scaleapplications. This inefficiency results in either low outputs of purewater or in extremely high power requirements. Therefore, known devicesare either incapable of supplying the quantity of pure water reqiired,or require such high power inputs as to result in unacceptableenvironmental pollution.

Some known devices have somewhat remedied the inefficiency of thedistillation process by utilizing solar energy as a means of augmentingthe power input. The solar energy is commonly utilized during thevaporization step in the distillation process. However, these devicesvaporize the water at atmospheric conditions, and the heat inputrequired to vaporize water at atmospheric conditions is quite large.Therefore, the output of such devices is quite limited. These devicesmust be either unreasonably large or require large solar energy transferdevices. Thus, there are known devices which utilize solar energy in thevaporization step which employ solar grids covering several acres ofarea, and large amounts of land area are consumed by the solar heatingmeans itself.

A further drawback of known devices results because the vaporization andcondensation steps are carried out in a common chamber. Thus, thedistillate often becomes recontaminated due to its proximity with thesolid residue originally removed therefrom. It is for this reason thatmany of the known distillation devices provide recirculation systems forrecycling the distillate in an attempt to assure total removal ofsubstantially all of the solid contimanants. However, because of theabove-mentioned proximity of the distillate and the solid residue, knownprocesses are somewhat self-defeating. Because of the recyclingprocedure, the net output of known devices is further limited and totalseparation, along with efficiency, are goals which, in many ways, areexclusive of each other.

As is well known, as the pressure of a system is decreased, thesaturation temperature of water in that system also decreases. Forexample, at atmospheric pressure, the saturation temperature of water is212° F., at 10 psia it is 193.21° F., at 5 psia it is 162.24° F., at 1psia it is 101.74° F., and at 0.0886 psia it is 32.02° F. (the triplepoint). Therefore, the power required to raise water to the saturationtemperature is decreased as the pressure of the system is decreased.This fact is utilized by some known distillation systems. However, dueto the nature of the elements used by these devices to produce thereduced pressure environment, only a small amount of liquid can betreated at one time. Furthermore, these devices do not produce acontinuous flow through the distillation apparatus. Thus, the salinewater is flooded into a chamber, the chamber is then closed off, areduced pressure condition is then produced in the chamber, and thenheat is input into the saline water to vaporize it. Therefore, inflowinto the distillation apparatus is interrupted while the vaporizationprocess is occurring, and the production of pure water of the system istherefore limited. Such a system is therefore not suitable fordesalinating extremely large quantities of water. Furthermore, due tothe nature of the pressure reduction step, the vaporization step iscarried out in a chamber which communicates with the condensationchamber in such a way that the distillate is exposed to the solidresidue, therefore producing the above-discussed possibility ofrecontaminating the distillate and thereby reducing the effectiveness ofthese systems.

In the device embodying the present invention, water is heated utilizingsolar energy and then transferred to a vacuum chamber where it isvaporized and the water vapor separated from the solid residue in acontinuous flow process. The water vapor is then transferred to aseparate condensing chamber where it is condensed to form pure distilledwater.

SUMMARY OF THE INVENTION

The saturation temperature of the contaminated water being vaporized bythe distillation apparatus embodying the present invention is very lowas compared to the saturation temperature thereof at atmosphericpressure. Furthermore, condensation of the water vapor occurs at, ornear, atmospheric pressure and therefore the water vapor is at, orbelow, the saturation temperature of water at atmospheric pressure.Therefore, solar energy can be utilized to supply sufficient heat inputto raise the temperature of large quantities of contaminated water abovethe saturation temperature required in the vaporization processoccurring in the evaporation chamber. The water vapor is thentransferred to a condensation chamber wherein the pressure is at, ornear, atmospheric pressure, hence less heat has to be removed from thewater vapor to condense it, and the condensation step occurs quiterapidly. Once vaporized, the water vapor and the solids dissolvedtherein are separated, and the vapor is condensed in a separate chamber,thereby substantially reducing the possibility of recontamination of thedistillate with solids which have been removed from the contaminatedwater by the distillation process.

Hence, the apparatus and method embodying the present invention iscapable of efficiently desalinating extremely large quantities of waterwhich have been contaminated by solid particles being dissolved therein.The device can therefore utilize solar power to distill suchcontaminated water with an efficiency which is quite high as compared toknown devices.

The apparatus embodying the present invention comprises a pump meanslocated in a large body of water which has been contaminated by solidcontaminants dissolved therein, such as a river or a salt sea. The pumptransfers water from the body of water to a solar heating grid acrosswhich the contaminated water flows. The solar heating grid transferssolar energy to the water flowing thereacross in order to raise thetemperature of that water to a predetermined level. A second pump meanstransfers the water from the solar grid to a storage means when thatwater has attained a prescribed temperature. Recirculation means arealso provided to maintain the water on the solar heating grid until theprescribed water temperature has been attained. Another pump means islocated in the storage means to transfer the water stored therein intothe evaporation system of the apparatus.

The evaporation system comprises a dome structure having a piping systemtherein through which the water is circulated from the storage means.The dome structure also serves as a condensation means and thereforeexposes the water being circulated through the piping system therein tothe condensing vapors which preheat the water in the pipes of the domestructure, as well as removes heat from the water vapor during thecondensation step.

From the dome structure, the water is transferred to a heater meanslocated adjacent the dome structure. In the heater means, solar energyis focused on the water to raise it to a predetermined temperature. Inthe heater means, auxiliary heat input means can be used to compensatefor reduced sunlight on cloudy days, or to augment the solar energyinput and thereby further increase the output of the apparatus embodyingthe present invention.

A vaporizing chamber is positioned adjacent the above-mentioned heater,and the heated water is transferred thereto. Vacuum pumps are associatedwith the vaporizing chamber to reduce the pressure in the vaporizingchamber to a level so that the temperature of the incoming water isabove the saturation temperature of that water. The water is sprayedonto moving belts in the vaporization chamber and vaporizes.

The water vapor is removed from the vaporization chamber by the vacuumpumps, and the solid residue, and the sludge, remains on the belts inthe vaporization chamber. The residue and sludge is removed from thebelts by means such as doctor blades, and is transferred to a removalsystem and is removed from the vaporization chamber.

The water vapor is transferred to the aforementioned dome wherein it isexposed to the pipes containing contaminated water. As the dome is at,or near, atmospheric pressure, the water vapor rapidly condenses towater and can be removed as pure water.

The system is so efficient that it is virtually self-supporting duringhot, sunny days and can sustain operation for several days withoutadditional sunlight before extensive auxiliary heating is required.Therefore, the apparatus and method embodying the present invention canbe used for desalting extremely large bodies of water, such as rivers,in an efficient manner which does not itself pollute the environment.

Furthermore, the apparatus and method embodying the present inventionproduces a total reduction of contaminated water to a condition ofeither fresh water or a solid contaminant. The device can therefore beused extensively in re-cycling water for pollution control purposes,allowing the removal of valuable compounds, chemicals, and elements frompolluted water while at the same time providing water that can berecycled through the plant again and again.

Because of the non-polluting and efficient manner in which the apparatusoperates, it can safely be utilized in highly populated areas, and istherefore effective to provide such areas with a source of pure water.

OBJECTS OF THE INVENTION

Accordingly, it is the main object of the present invention to separatelarge quantities of pure water from a body of water which has beencontaminated by solid contaminants dissolved therein.

It is a further object of the present invention to produce totalseparation of the contaminated water to a condition of either pure wateror solid residue.

It is yet another object of the present invention to desalinate largequantities of water in an efficient and economical manner.

It is still a further object of the present invention to desalinatewater in such a manner that large quantities of solid residue can beeasily salvaged.

It is still another object of the present invention to desalinate largequantities of water with an apparatus which produces a minimum ofenvironmental pollution.

It is yet a further object of the present invention to desalinate largequantities of water with an apparatus having low power requirements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a plan view of the apparatus embodying the presentinvention located adjacent a body of contaminated water;

FIG. 2 is a vertical, sectional view taken along line 2--2 of FIG. 1;

FIG. 3 shows a detailed section of the solar heating grid utilized inthe apparatus of the present invention and is taken along line 3--3 inFIG. 1;

FIG. 4 shows a recirculation system used in the apparatus of the presentinvention and is taken along line 4--4 in FIG. 1;

FIG. 5 shows a perspective, cut-away view of the dome structure utilizedin the apparatus of the present invention;

FIGS. 6a and 6b show details of the vaporization apparatus used in thepresent invention and are taken along line 6a--6a in FIG. 5, and 6b--6bin FIG. 6a, respectively;

FIG. 7 is taken along line 7--7 of FIG. 6a and shows details of the beltsystem used in the vaporization apparatus;

FIG. 8 is a perspective view of the belts used in the system of FIG. 6a;

FIG. 9 shows details of a drive system used to drive the belts shown inFIGS. 7 and 8 and is taken along line 9--9 of FIG. 7.

FIGS. 10 and 11 show details of a system used to remove solid residuefrom the vaporization apparatus shown in FIGS. 6a and 6b;

FIG. 12 shows details of the heating dome used in the apparatus of thepresent invention;

FIGS. 13a-13c show details of a heater unit utilizing solar energy toheat the contaminated water prior to indroduction thereof into thevaporization chamber of the apparatus of the present invention;

FIG. 14 shows details of a boiler system which is utilized with the FIG.13 heater;

FIG. 15 is a schematic diagram of the system used to transfer solarenergy to the water in the FIG. 13 heater;

FIG. 16 shows further details of the solar transfer means shown in FIG.15;

FIG. 17 is a perspective view of the boiler shown in FIG. 14; and

FIG. 18 is an overall schematic of the placement of solar transfer meansused in conjunction with the FIG. 13 heater.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Shown in FIG. 1 is a distillation apparatus 20 located adjacent a bodyof contaminated water, such as a river or sea 22, which has solidcontaminants dissolved therein. A first pump 24 is located in the sea 22and removes water therefrom. The removed water is transferred through aconduit 26 and into a header 28 which surrounds the apparatus 20 alongthe outer perimeter thereof. From the header 28, the contaminated waterflows across a solar heating grid 30 comprised of four sections 32-38.Each grid section comprises a plurality of parallel flow channels 40. Asshown in FIG. 1, the flow channels of each grid section are parallelwith each other and are perpendicularly disposed to the flow channels ofthe adjacent grid sections for inducing turbulence in the water flowingacross the solar heating grid to thereby increase the heat transfer fromthe grid to the water flowing thereacross. Centrally disposed of thedistillation apparatus 20 is a storage means 46 comprised of a moat ortrough 48 which connects to the inner perimeter of the solar heatinggrid 30 at sections 52-56. Flow arrows 58 indicate the direction of flowacross the solar heating grid 30 into the trough sections of trough 48.Located above storage means 46 is a heat transfer structure 64 comprisedof a dome 66 and four vaporizer units 68-74 connected to the dome 66 byconduits 76. A pure water transfer duct 80 comprises a first section 82connected to the dome 66 and traversing across the solar heating gridsection 34 into header 28 and a circular second section 84, which islocated in the header 28 and traverses the outer perimeter of theapparatus 20 in that header to connect with a third section 86. Thethird section 86 is connected to any suitable pure water usage orstorage device. By locating second section 84 in the header 28, the hotpure water is utilized to transfer heat to the incoming contaminatedwater and thereby raise the temperature of that contaminated water tomake effective use of the energy input into apparatus 20. A plurality ofconveyor belts 90-96 are connected to the vaporizer units and extendradially outward therefrom to the outer perimeter of the distillationapparatus 20 and transfer the solids produced in the distillationprocess to convenient storage and/or usage devices. Arrows 98 indicatethe direction of movement of the conveyor belts.

FIG. 2 is an elevation view on section 2--2 of the distillationapparatus 20. As shown in FIGS. 2 and 3, the solar heating grid 30 ismounted on a concrete base 100, which, in turn, is mounted on a dirtfoundation 102 which supports the entire apparatus 20. The concrete base100 comprises a horizontal section 104 which attaches at one end toheader 28 and at the other end to vertical section 106 to form an outerwall of the trough 48. Another horizontal section 108 forms the bottomwall of the trough 48 and connects to the outer surface of wall 110 of amain storage tank 112 having a base 114 supported in the dirt foundation102. The main storage tank 112 is large enough to contain enough waterto supply the apparatus with water for approximately three days withoutinterruption. A plastic material covering 116 covers the solar heatinggrid and the inside of the main storage tank 112. As shown in FIG. 2, amain platform 120 forms a mounting base and is supported by main supportcolumns 122 and end support columns 124 mounted on the upper edge of theconcrete wall 110. The main platform 120 is formed of reinforcedconcrete having reinforcing ties 126 therein and supports thereon thedome 66 and the vaporizing units, as well as the residue removalelements, such as conveyor belts 92 and 96. Located in tank 112 is asecond pumping means 130 comprising a main pump 132 and an auxiliarypump 134 for removing water 136 which has been stored in the mainstorage tank 112. The two pumps feed into conduits 137 and 138 which areconnected by a T-connection 140 to a common riser conduit 142. Thecommon riser conduit 142 is comprised of a first section 144 and asecond section 146 which passes through the main platform 120 upwardlyinto dome 66. The dome 66 is comprised of an outer wall 148 and an innerwall 150 and a plurality of preheater pipes 152 located inside the domeadjacent inner wall 150 and connected to outlet end 154 of section 146of the riser conduit. As will be later discussed, a plurality ofhorizontal connecting conduits 158 interconnect vertical sections 160 ofthe preheater pipes 152. The conduits 76 and 162 connect the vaporizerunits to the dome 66. Either, or both, of the pumps 132 and 134 can beused to withdraw water from the storage tank 112 and transfer it to thepreheater pipes 152. The pumps 132 and 134, like pump 24, should bedurable, and resistant to corrosion by the contaminants dissolved in thecontaminated water being desalinated by the distillation apparatus 20.

As shown in FIG. 4, water removed from the sea 22 by the pump 24 istransferred through conduit 26 into a pipe coupling which distributesthe water from conduit 26 into header 28 wich is comprised of a footingsection 172 and two wall sections 174 and 176, which connects to thehorizontal portion 104 of the concrete base 100. As shown in FIG. 4,wall 176 forms with horizontal section 104 a spillover 178 over whichthe water from trough 28 flows onto the solar heating grid 30. The solarheating grid transfers solar energy to the water flowing thereacross toraise that water to a predetermined temperature. A recirculation system180 comprising recirculation pump 182 having an intake 184 and atemperature control 186 and a return conduit 188 removes water fromtrough 48 and returns it to header 28 for further heating thereof. Asshown in FIG. 4, the vertical wall 106 forms with horizontal section 104a spillway 190 over which water from solar heating grid 130 flows intotrough 48. When the water in trough 48 reaches the proper temperature,the recirculation pump 182 is shut down and transfer pump 192 comprisingtemperature control unit 194 and transfer conduit 196 is started totransfer water from the trough 48 into main storage tank 112 over wall110. The trough 48 is sized to contain approximately a one day supply ofwater so that the apparatus 20 can operate uninterrupted for 4 full dayswithout withdrawing water from the sea 22. A plurality of pumps 182 and192 are located in the trough at various points therein, and, like theother pumps in the device, are durable and resistant to corrosion fromthe solid contaminants contained in the water being desalinated by thesystem. The pumps 182 and 192, like pumps 132 and 134, are submersibleand hence any heat generated thereby is utilized to raise thetemperature of the water in the storage system. For clarity's sake, theouter edge of the main platform 120 and the corresponding support column124 is not shown in FIG. 4; however, the main platform, as shown in FIG.2, covers the entire top surface of the main storage tank 112.

Shown in FIG. 3 is a detail of the solar heating grid 30 taken alongsection 3--3 of FIG. 1. As shown in FIGS. 1 and 4, the solar heatinggrid 30 is at a higher elevation than the bottom of the main storagetank 112 and surrounds the outer periphery of that tank so that the mainstorage tank is centrally located within the solar heating grid and theouter perimeter thereof is circular.

FIG. 3 best shows the details of the solar heating grid 30. As shown,the solar heating grid comprises a gravel sub-base 200 overlying thedirt foundation 102, and upon which a layer of reinforced concrete 202is overlaid. In the preferred embodiment, the concrete layer 202 isapproximately 4 inches thick. The concrete is covered with an extruded,rigid, insulation board 204. In the preferred embodiment, the insulationboard is either polystyrene or polyurethane. A plurality of protrusions206 are formed on the insulation board to define the flow channels 40,as shown in FIG. 1. The insulation board is covered with a coating 208,which, in the preferred embodiment, is Teflon. This coating correspondsto the covering like shown in FIG. 2, and, in fact, may be the samecoating. The insulation board comprises a plurality of sections, such assection 210, which comprises longitudinal edges 212 and 214 and a topsurface 216 which may have a protrusion thereon which is locatedintermediate the longitudinal edges 212 and 214. A protrusion 220 ispositioned on the top surface 210 to project outwardly from longitudinaledge 212 so that the base 222 of the protrusion 220 extends outwardlyfrom ledge 212 to form with longitudinal edge 212 a shoulder 224. Alongitudinal edge 214 is received in the shoulder 224 with protrusion220 overlapping the longitudinal edge 214 to interconnect the pluralityof sections 210 together to form the quadrants of the solar heatingrigid 30. Glue, or other suitable fastening means, can be used to fixthe plurality of sections together, and to the concrete base along thelower surface 226 of each of the sections 210.

In the preferred embodiment, the coating 208 is a dead black Teflon.Teflon is used for its high heat resistance and for its non-adhesioncharacteristics so that nothing will stick to it, including any possiblesalt deposits. Even though some of the water molecules passing over thesolar heating grid will evaporate, the percentage of such evaporationwill be so small that solid percipitation will be negligible, and theamount of water lost in the evaporation will also be negligible.

In the preferred embodiment, the flow velocity of the water crossing thesolar heating grid will be adjusted so that the temperature of thatwater will be between 175° F. and 195° F. As discussed above, the flowvelocity is somewhat controlled by the temperature controls 186 and 194of the pumps positioned in the trough 48.

Another embodiment of the solar heating grid 30 will comprise aplurality of sections 210, each comprising only a single protrusion 220.This embodiment is the preferred embodiment, and is the one shown inFIG. 3.

As shown in FIG. 2, the main storage tank 112 will also be lined withinsulation board similar to insulation board 204. Of course, the storagetank lining will not need protrusions similar to protrusions 206.Furthermore, the insulation board in the storage tank will also beplaced over a concrete base 230 which is similar to the concrete base100 forming the base of the solar heating grid 30, the base 114 of thestorage tank 112 and the wall 110 of that storage tank.

As shown in FIG. 1, the preferred embodiment comprises a square storagetank, however, a circular storage tank may also be used.

As shown in FIGS. 2, 5 and 12, dome 66 forms a heat transfer structurewherein water from main storage tank 112 is preheated and water vaporfrom vaporizer units 70 through 76 is condensed. As shown in FIGS. 1 and2, the dome 66 is located centrally of the distillation apparatus 20 andsupported on the main platform 120.

The arrangement of the preheater pipes 152 is best shown in FIG. 12,wherein water from the main storage tank is pumped through the section146 of the riser pipe to top end 154. Two deadend pipes 250 and 252 areconnected to the top end 154 and are mounted on the deck 254 of thedome. The deadend pipes comprise blank ends 256 and 258 mounted ondiametrically opposite sides of the deck 254. The piping system furthercomprises pipes 260 and 262 having horizontal legs 264 and 266,respectively, mounted on diametrically opposite sides of the risersection 146 in the deck 254. Blank ends 268 and 270 of the pipes 260 and262 are also located in the deck 254. As shown in FIG. 12, the pipes250, 252, 260 and 262 divide the deck 254 into quadrants.

As shown in FIG. 12, a plurality of connecting pipes 158 connect thedeadend pipes 250 and 252 to the pipes 260 and 262, and a plurality ofdeck pipes 274 connect the horizontal legs 264 and 266 of the pipes 260and 262 to outlet conduits 162. As shown in FIG. 2, the outlet conduits162 are connected to the vaporizer units. The pipes 250, 252, 260 and262 serve as structural members to hold the dome upright and to retainwater vapor transferred from the decondensing units until it iscondensed into water. Furthermore, the pipes provide cooling surfacesupon which the water vapor condenses and trnsfers the heat ofcondensation to the water being transferred from the main tank 112 topreheat that water. Therefore, water transferred into the dome from themain storage tank flows through all of the structural members. The waterflows downward through deadend members 250 and 252, across connectingpipes 158 into pipes 260 and 262, and through deck pipes 274 intoconduits 162. The water therefore flows on a circuitous path through theentire dome structure 66. The circuitous path maximizes the heattransfer characteristics of the heat transfer structure. Furthermore,the deadened members induce turbulent flow within the pipes to furtherincrease the heat transfer between the condensing vapors and the waterflowing in the pipes. Furthermore, the pipes are manufactured of athermally conductive material to further promote the aforementioned heattransfer.

From the dome 66, the water flows into final heaters 290, one of whichis associated with each of the vaporizer units and is located adjacentthe dome and the vaporizer unit. As shown in FIG. 13a, a valve 291 ispositioned in conduit 162 and connects to a conduit 292 leading to aboiler 294. The boiler 294 is best shown in FIGS. 14 through 17, andcomprises two pieces. A first piece is shown in FIG. 14, and comprisesan aluminum casting 296 with vanes 298 on the outer periphery thereof.As shown in FIG. 17, these vanes stop short of the ends of the boileralternately on each side at points 302, shown in FIG. 15. A segment ofheavy aluminum pipe 304 is fitted over the outer surface of the aluminumcasting and welded at point 306, and also around the top and bottom ofthe boiler. Thus, a closed vessel with alternate end fins is produced.The vessel forces the water to run first right and then left, as shownin FIG. 16, as it moves up through the heat exchange chamber 308 of theboiler from conduit 292 into inlet 310, and out through discharge outlet312. The inlet and outlet are each tapped and threaded.

As shown in FIG. 15, the transverse cross-section of the boiler isC-shaped having an opening 314 and an inner surface 316 which comprisesa peaked section 318. The peaked section 318 comprises two oppositelysloping planar surfaces 320 and 322 and an apex 324 formed by the innersection of the two planar surfaces. The peaked section runslongitudinally of the boiler and therefore serves as a ray dispersalmeans for dispersing solar rays entering the enclosure through opening314. This feature will be discussed in greater detail below. The arrow325 shows the path followed by the water as it flows through the heatexchange chamber 308.

As shown in FIG. 1, in the preferred embodiment there are four vaporizerunits. Hence, there will be four final heaters. The boilers associatedwith each of the vaporizer units are oriented to receive solar radiationreflected by the first solar-reflectors 326. The casting 296 is anodizeddead black on the inside surface 316 to absorb the solar energy directedtoward that surface. The temperature of the water passing through theboiler can be raised to any suitable level, even past the saturationtemperature of that water, if so desired. The unit has a temperaturecontrol means 330 associated therewith which controls the flow rate ofthe water flowing through the boiler according the temperature desiredfor the effluent. The temperature control unit 330 can also be set tomaintain the temperature of the water in the boiler below a level whichwould damge that unit, for instance 500° F., which may soften thealuminum to a point that it loses strength and ruptures under thepressure in the system.

An alternative embodiment of the boiler would comprise a stainless steelconstruction, wherein the water temperatures can be raised to extremelyhigh levels to produce super-heated fluids.

As shown in FIG. 13a, a conduit 336 is connected to discharge outlet 312and is coupled to a valve 338 which directs the heated fluid to eitherconduit 340 or conduit 342 in accordance with the condition of thedistillation apparatus, as will be later discussed. Conduit 340 isconnected to conduit 162 which is connected to an entrant header 346 ofa solar energy transfer heater 348. The transfer heater 348 comprises apluraity of horizontal pipes 350 connected to the entrant header 346 andan effluent header 352, which is connected to a riser pipe 356. Theriser pipe is also shown in FIG. 6a. Solar energy from second solarreflectors 357 is concentrated on the pipes 350 by third solarreflectors 360, as shown in FIG. 1. The conduit 342 connects to theriser pipe 356 to bypass the solar energy transfer heater 348, if sodesired.

FIG. 13c shows the arrangement of the pipes 350 in the solar energytransfer heater 348. As shown, the pipes are arranged in rows which eachhave a steadily rising plane from the forward location 362 located onthe outside of the unit, to the rearmost position 364 located on theinside of the unit. The rising plane enables each of the pipes toreceive aportion of the light from the solar reflector 360 and the angleof contact between the light and the pipes will tend to reflect heatwhich has not been absorbed by each individual pipe into contact withsurrounding pipes. Therefore, a major portion of the solar energy isutilized. The pipes are also staggered in vertical columns to maximizethe heat transfer from an auxiliary heater 370 shown in FIG. 13b.

The auxiliary heater can, like the other pumps and motors, be eitherelectric or fuel powered and is used to augment the heat transfer fromthe solar reflectors on cloudy days, or after dark.

The vertical and horizontal space in between the pipes 350 is arrangedto produce a minimum of shadowing as well as a maximum area to receiveheat from the auxiliary heaters. Therefore, the combination of theboiler 294 and the solar energy transfer heater 348 is a unique designwhich obtains a very high efficiency from three different heat sources,separately or simultaneously. First, when the sun is not shining, extraheat is added by the auxiliary heater 370. The heat pipes 350 arestaggered so that direct impingement is obtained on every pipe as theheat rises through the transfer heater 348. Second, the pipes arearranged so that the light from the solar reflectors penetrates 50% ofthe way in from each side with equal surface exposure on each tube.Third, the inlet design of the entrant header 346 is arranged andconnected to the conduit 162 such that high temperature water or steamfrom the boiler 294 will equalize itself and provide a uniformtemperature rise throughout the boiler 348.

As shown in FIGS. 1 and 14, solar energy is reflected by secondreflector 357 onto third reflector 360. As shown, the second reflector357 is a segment of a cylinder and produces a vertical concentratedlight band on reflector 360. The inside surface of the reflector 357 isa highly reflective coating, and in the preferred embodiment, thereflector 357 is a segment of a cylinder about 5 meters high and 10meters wide, with a radius that produces a vertical concentrated lightbeam of about 1/2 meter wide by approximately 5 meters high at adistance of 30 meters.

The light beam is caught by reflector 360 which is oriented to be in ahorizontal plane, or, particularly disposed to the second reflector 357.The third reflector, in the preferred embodiment, is one meter long andis approximately 6 meters high. The third solar reflector 360 has aradius sufficient to concentrate a light beam 1/2 meter square on theside of the boiler pipes 350. The configuration shown in FIG. 13aproduces a square light pattern sized to fit the solar energy transferheater 348, as well as being sized for ease of manufacture. The thirdsolar reflector 360 can be either a flat or a curved configuration. Thereflector 357 is mounted and controlled so that as the angle of the sunchanges, that reflector will follow to be properly oriented. The thirdreflector 360 is also hingeably mounted to be automatically orientedproperly with respect to the solar energy transfer heater 348. The firstsolar reflector 326, shown in FIG. 14, is similar to the second solarreflector 357, shown in FIG. 1; however, the second stage reflector isslightly smaller than the solar reflector 360. The second stagereflector concentrates light on the boiler 294.

For the most efficient exposure of the reflectors to the sun's rays,these reflectors are set so that they will be exposed to the rays of thesun for a maximum number of daylight hours each day. An example of thesetting of the reflectors is shown in FIG. 18. As shown in FIG. 18, thesecond stage reflector, which can be either reflector 380 or reflectors360, is a flat reflector. As shown in FIG. 18, the solar concentratorunit comprised of either first reflector 326 or second reflector 357 andthe second stage reflectors is oriented so that part of the time thesecond reflector is used and part of the time the first stage reflectoris used for the first reflection. Thus, when the sun's angle reaches apoint to place the device 20 between the sun and the relector, the sun'srays are reflected directly from the first stage reflector to the pipes350, and as the angle with respect to the sun changes, the sun's raysare reflected from the first stage reflector to the second stagereflector and then to the pipes 350. A temperature controlled unit canbe used to control the movement of the solar reflectors. Any suitablecontrol means for controlling the solar reflectors and the elementsassociated therewith can be used, and an example of such control meansis discussed in my co-pending application.

As shown in FIG. 6a, fluid from final heater 290 is transferredtherefrom into a vaporizing chamber 400 by the riser pipe 356. Thevaporizer unit is comprised of an outer casing 402 having a double upperwall with outer wall 404 and inner wall 406 defining therebetween apassageway 408 and lower wall 410 connected to casing 412 of the finalheater 290 by weldments 414, or the like. Passageway 408 is sealed by aone-way valve 416 at one end thereof. Connected to outer casing 402 atthe one end of the passageway 408 is vapor conduit 76 which is separatedfrom the passageway 408 by the valve 416. As will be discussed below,water vapor produced in vaporizing chamber 400 is pumped into passageway408 by a plurality of high speed pumps 420, and thence into conduit 76for movement into the condensing area of the device 20.

The outer casing of the vaporization unit has a reinforced rib design,as shown in FIG. 6a, and comprises a plurality of ribs 424 which serveas stiffeners for the casing. The reinforcement of the casing isnecessary because this chamber is under vacuum, and withoutreinforcement, the wall structure would have to be extremely heavy toprevent it from buckling due to the atmospheric pressure thereon. Theouter casing in the preferred embodiment is steel with the stiffnesswelded thereon. A plurality of support columns 426 connected to the base410 and the main platform 120 serve to add additional support to thevaporization unit.

As shown in FIGS. 6a and 6b, the vaporization unit comprises a pluralityof belts 430 mounted on rollers 432 and 434 in the vaporizing chamber400. As is best shown in FIGS. 6b and 7, the belts are each inclined intwo planes. Thus, each belt is pitched downwardly slightly from itsanchor point, for example roller 434, and upwardly in a directiontransverse thereto. Thus, as shown in FIG. 6b, the belts are inclinedwith respect to the horizontal plane of the main platform 120, and henceinclined along their longitudinal axis, and as shown in FIG. 7, are alsopitched along an axis transverse thereto. Thus, as shown in FIG. 6b, abelt 430' is inclined upwardly from left to right in FIG. 6b, and fromthe front of the unit upwardly to the back of the unit. The belts aremoving parallel to the plane of the paper in FIGS. 6a and 6b, andperpendicular to the plane of the paper in FIG. 7.

The riser pipe comprises first section 440 oriented to runlongitudinally through the bottom thereof to a location closely adjacentthe pumps 420, a horizontal second section 442, and a third verticalsection 444 which runs from a position closely adjacent the pumps 420down the side of the vaporizing chamber 400 on the inside thereofbetween rollers 434 and the inside of casing 402 to a position spacedfrom the bottom 410 of the vaporizer unit. A plurality of branch pipes446 are each connected to the section 444 of the riser pipe and extendfrom section 444 inwardly of vaporizing chamber 400 toward thelongitudinal center line thereof. Each of the branch pipes 446 comprisesa plurality of holes spaced along the length thereof and acts as asprayhead for spraying liquid which has been heated in final heater 290and is flowing in the riser pipe 356 onto the belts 430. Each belt 430has a branch pipe 446 associated therewith. Fluid sprayed from thesprayhead contacts the moving belts 430 on the top thereof as well asthe bottom thereof, and is transported thereby.

The pumps 420 maintain a vacuum condition in the vaporizing chamber 400.The liqiud in final heater 290 is heated to a temperature which will beabove the saturation temperature corresponding to the pressuremaintained in the vaporizing chamber 400, and therefore when the liquidis sprayed onto the moving belts, it vaporizes very rapidly. Thevaporization is augmented because the belts develop very thin layers ofwater, which expedites the vaporization process. Because the belts arepitched in two planes, the vaporization process is further enhanced.

In the preferred embodiment, the belts 430 are either stainless steel orhigh temperature fiberglass-filled Teflon material.

A plurality of doctor blades 450, or other suitable means, are mountedin the vapirizing chamber 400 adjacent the rollers 432 to remove thesolid residue which adheres to the belts 430 after the liquid hasvaporized and has been separated therefrom. The residue is removed fromthe belts and is transferred to a dump-system which will be discussedbelow.

The rollers 432 and 434 are driven by motors 452 and 456, respectively,through a gear train which comprises a driving gear 460 associated witheach roller and an idler gear 462 located below and meshing with thedrive gears.

As shown in FIG. 5, the casing of each vaporizing unit comprises a fixedportion 466 and a movable cover 468. A moving means 470 comprises atriangular cart 472 fixed along one side thereof to the outside of themovable cover by fasteners 474 and mounted on a support beam 476 bywheels 478 attached to another side of the cart 472 by wheel mounts 480.The support beam 476 is a T-shaped beam having an upper flange 482 whichhas a width corresponding to the width of the wheels 478, so that thosewheels roll, and are guided, thereon. The support beam is, itself,mounted on the main platform 120. When service is to be performed on theinside of the vaporizing chamber 400, the cart 470 is moved outwardlyalong the support rail 482, thus exposing the inside of the vaporizingchamber 400. For convenience, in the preferred embodiment, half of therollers are mounted on the cover and half of the rollers are mounted onthe fixed portion of the body of the vaporizing unit.

To facilitate removal of the cover, the drive gears 460 are mounted onthe cover and are attached to the rollers 432 and/or 434 by stub shafts490 (FIG. 7) having slots 492 in one end thereof which engagecooperating parts of the rollers to form a splined connection 494. Therollers and stub shafts are supported by flanges 496, or other suitablemeans mounted on the cover 468.

To achieve maximum production, the preferred embodiment comprises anairflow means 500 comprising a conduit 502 connected to the casing 402of the vaporizing unit and to the inner wall 150 of the dome 66. Aplurality of electric heaters 504 are located within the conduit 502 forheating the air flowing into the vaporizing chamber 400 through opening506 from the inner volume of dome 66. As shown in FIG. 6a, opening 506is located adjacent the bottom 410 of the unit and the end of section444 of the riser pipe. The feed pipe and system 500 also serves as arecirculation system for recycling water vapor back into thevaporization chamber to achieve further purification thereof. Theheaters 504 are maintained at a temperature which insures that airflowing into the vaporizing chamber 400 is at or above the meantemperature in the chamber 400.

Therefore, the water heated in final heater 290 is sprayed onto movingbelts 430. The water vapor is mixed with the air from the auxiliarysystem 500 and withdrawn from vaporizing chamber 400 by pumps 420 whichtransfer the mixture into the passageway 408, and from there intoconduit 76 leading to the interior of dome 66. The solid residue, andsludge, left behind through precipitation onto the belts 430 during thevaporization process is removed by the removal means, such as doctorblades 450, and moved into a dump system 510. In the preferredembodiment, the bottom two belts 512 and 514 have no water placed onthem so that they can be used to make final evaporation of any waterthat overflows the belts above them. Therefore, no water will accumulatein the bottom of the chamber. Furthermore, in the preferred embodimenteach belt has a deflector thereon so that no water is allowed to run onthe inside of the belt where deposit would build up, thus causingproblems.

As shown in FIGS. 6a, 10 and 11, the dump system 510 is positionedsuperadjacent conveyors 90-96 which are driven by conveyor drives 550.The dump system 510 drops the solid residue and sludge 552 onto themoving conveyors for removal from the device 20. The dump system 510comprises three pairs of trap doors 560, 562 and 564 hingeably attachedto an outer casing 566 by pivot pins 568 mounted in flanges 570. Asshown in FIG. 11, the trap doors move from a horizontal closed positionto an open position wherein each of the doors of a pair of doors is atan angle to the horizontal. A door stop 572 is mounted on the casing 566and is located intermediate sides 574 and 576 of the casing. Door mounts578 also have stops thereon for limiting the movement of the trap doors.As shown in FIG. 10, the movement of each of the trap door pairs iscontrolled by a door control system 580 comprising an actuating cylinder582 having a piston controlled cylinder arm 584 connected to aconnecting link 586 by a bell crank 588 pivotally mounted on flange 570of door mount 578. Connecting link 586 is connected at one end of afollower arm 590 which is connected at the other end thereof to pivotpin 568 of door mount 578. Therefore, actuation of cylinder 582 causesbell crank 588 and follower arm 590 to rotate, thereby causing the trapdoors to open. Actuation of cylinder 582 is controlled by a servocontrolsystem 592 according to the amount of solid material supported by thetrap doors. A vacuum line 594 is connected to branch lines 596 and 598to produce a vacuum in chambers 600 and 602 formed between the trapdoors. Therefore, the doors can be opened without breaking the vacuummaintained inside vaporizing chamber 400.

The normal cycle for the dump system 510 is as follows: the beltsaccumulate solids and when the solids reach a sufficient thickness, theywill be removed from the belts by the doctor blades as the belts passaround rollers 432. The solids then drop onto the top of trap doors 560,and when sufficient solids have been built up on the doors 560, a vacuumis drawn in chamber 602 and then the doors 560 are opened to allow thesolids thereon to fall into chamber 602 onto doors 562. The doors 560are then closed and the chamber 600 evacuated. When the chamber 600reaches a sufficiently high vacuum, the doors 562 are opened and thesolids are deposited on doors 564. The doors 562 are closed, and thedoors 564 are opened to deposit the solids onto the moving conveyor beltsubjacent the dump system 510. In this way, the solids can be removedfrom the vaporizing chamber 400 without breaking the vacuum conditionspresent in that chamber. Therefore, the distillation process can be acontinuous one without need of interrupting the process to place morewater in the vaporizing chamber, or to remove solids from that chamber.It is for this reason that great amounts of contaminated water can beefficiently distilled in a continuous process. As the solids movethrough the dump system 510, further solids can be deposited on the topdoors 560 from the vaporizing chamber, thus maintaining the continuityof the operation.

In the preferred embodiment, the pumps 420 shown in FIG. 6a are twodirectional, high speed vacuum pumps having shafts which run in oppositedirections and are powered by two totally enclosed electric motors, onefor each shaft. The pumps remove the water vapor from the vaporizingchamber 400 and cause it to flow into conduit 76 via passageway 408. Asshown in FIGS. 2 and 5, conduit 76 is in fluid communication with theinterior of dome 66, therefore the water vapor flows into the innervolume of dome 66 where it contacts the pipes 152 and is condensedthereon.

The condensed water vapor is collected in a collecting means 610 locatedin deck 254 of the dome 66. The fresh water conduit 80 connects to thecollection means 610 and transfers that pure water from the collectionmeans across the solar heating grid, into the header 28, and out of thedevice 20 into a convenient storage or utilizing means. By transferringthe hot water across the solar heating grid, the water is reheated andhence can transfer that heat to the water in the header 28 to increasethe temperature of that water toward the level at which the pumpingmeans located in trough 48 can move it into the storage tank 112.Therefore, the efficiency of the distillation device is maximized.

Therefore, the purpose of the piping system 152 is three-fold: First,the piping system provides a structural member to hold the fabric of thecondensing dome to retain the vapor until such time as that vapor iscondensed to water; second, the piping system provides cooling surfacesto promote condensing of the water vapor into water; and third, thepiping system transfers the heat from the condensing steam to theincoming water to heat that water to a predetermined temperature priorto input into final heater 290.

Having described the structural details of the distillation device 20, adescription of the operation thereof will now be presented withreference to FIGS. 1, 2 and 6a. Water is removed by first pump 24 fromsea 22 and transferred into header 28, where heat is transferred theretofrom the hot water and pure water transfer duct 80. The water moves overspillover 178 onto solar heating grid 30, where its temperature isincreased to a predetermined level by the transfer of solar energy tothe water flowing across the solar heating grid. The water flows overspillway 190 into trough 48 and is recycled by recirculation system 180until the temperature of the water reaches a predetermined level,whereupon the water in trough 48 is transferred by pump 192 into mainstorage tank 112. Pumps 132 and 134 then transfer water from the mainstorage tank into piping system 148 via riser pipe 142. The water andpiping system 152 is circulated through a circuitous path around thedome 66, where heat is transferred thereto from the water vaporcondensing inside the dome. The water is then circulated via conduits162 into final heaters 290, each associated with one of a plurality ofvaporizing units located adjacent the dome 66. The water is eitherpreheated in a boiler 294 or flows directly into an entrant header 346of the solar energy transfer heater 348. The water in the boiler 294and/or the transfer heater 348 is heated by either first solarreflectors 326 or second solar reflectors 357, respectively, to apredetermined temperature. The solar energy transfer heater 348 can alsobe heated by alternative means, such as auxiliary heater 370 shown inFIG. 13b. The water from either the solar energy transfer heater or theboiler 294 flows into the vaporizing chamber 400 via riser pipe 356. Theriser pipe 356 has a plurality of sprayheads each associated with one ofa plurality of moving belts located in the vaporizing chamber 400. Thewater is sprayed onto the moving belts by the sprayheads and is at atemperature which is above the saturation temperature corresponding tothe pressure in the vaporizing chamber 400. Therefore, due to acombination of the saturation conditions in the vaporizing chamber andthe turbulence induced by the movement of the belts in the vaporizingchamber 400, the water is caused to vaporize. The water vapor is mixedwith heated air inducted into the vaporizing chamber through anauxiliary system 500 from the internal volume of the dome 66 and iseducted from the vaporizing chamber by a plurality of pumps 420 into apassageway 408. The water vapor passes through a conduit 76 into theinternal volume of the dome 66 while the solids and sludge precipitatedfrom the water remain on the moving belts. When a sufficient thicknessof solid is built up on the belts, the solids are removed from the beltsby removal means, such as doctor blades 450, and moved into a dumpsystem 510. The solids move through a plurality of chambers in the dumpsystem 510 and are eventually deposited on conveyor means 90-96 withoutdisturbing the vacuum maintained in vaporizing chamber 400. The watervapor flowing into the internal volume of the dome 66 condenses on theoutside of the pipes in the piping system 152 and the pure watercollected in a collecting means 610 located in the deck 254 of the dome66 and transferred into a pure water transfer duct 80 by any convenientmeans, such as a pump, or other flow inducing means. The water is thenremoved from the distillation device to a disposal or utilizing meansvia a circuitous path which enables that pure water to transfer heat tothe incoming contaminated water to increase the temperature of thatcontaminated water toward the predetermined level. The condensing vaporsof the water vapor also transfer heat to that contaminated water,thereby maximizing the overall thermal efficiency of the distillationdevice 20. The casing of the vaporizing units is movable so that theinternal elements of the vaporizing chamber can be exposed for servicingthereof, and the solar reflectors are movable to insure maximumutilization of the sun's radiation during the daylight hours.Furthermore, the belts in the vaporizing chamber are tilted in twoplanes to further maximize the vaporization process due to theturbulence induced thereon by that tilting.

As this invention may be embodied in several forms without departingfrom the spirit or essential characteristics thereof, the presentembodiment is, therefore, illustrative and not restrictive, since thescope of the invention is defined by the appended claims rather than bythe description preceding them, and all changes that fall within themetes and bounds of the claims or that form their functional as well asconjointly cooperative equivalents are, therefore, intended to beembraced by those claims.

I claim:
 1. A distillation device comprising:a first water transfermeans for withdrawing contaminated water from a body of water havingsolid contaminants dissolved therein; a grid connected to said firstwater transfer means so that contaminated water received from said bodyof water flows across said grid, said grid having an outer peripheraledge and an inner peripheral edge and comprising a header located onsaid grid outer peripheral edge and fluidly connected to said firstwater transfer means so that contaminated water flows into said headerfrom the body of water, said header being fluidly attached to said gridso that contaminated water flows from said header onto said grid wherebycontaminated water flows from the body of water to said grid via saidheader, and a trough located on said grid inner peripheral edge andfluidly attached to said grid so that contaminated water flows into saidtrough from said grid, and means for transferring solar energy to saidwater flowing across said grid; a water storage means having a side wallattached to said grid trough so that contaminated water flowing on saidgrid flows into said water storage means via said trough; second watertransfer means connected with said water storage means for removingcontaminated water from said storage means; a third water transfer meanslocated in said trough and connected to said water storage means fortransferring water from said trough to said water storage means andtemperature control means connected to said third water transfer meansfor actuating said third water transfer means when the temperature ofsaid water in said trough reaches or exceeds said predeterminedtemperature so that only water having a temperature which equals orexceeds said predetermined temperature is transferred to said waterstorage means; a heat exchange structure connected to said water storagemeans; a recirculation apparatus mounted in said trough and connected tosaid header for recirculating said water from said trough back to saidheader prior to transferring water from said trough into said waterstorage means and temperature control means connected to saidrecirculation apparatus for actuating said apparatus when thetemperature of said water in said trough falls below a predeterminedtemperature; a vaporizer means connected to said heat exchange structurefor separating said water from said solid contaminants dissolvedtherein, said vaporizer means having a solar concentrator means fortransferring solar energy to said contaminated water flowing from saidheat exchange structure into said vaporizer means; vacuum producingmeans for producing a vacuum in said vaporizer means so that saidcontaminated water is vaporized under vacuum conditions to form watervapor and thereby separate said water from said solid contaminants, andsolid removing means connected to said vaporizer means for removing saidsolid contaminants from said vaporizer means; water vapor transfer meansconnected to said vaporizer means for removing said water vapor fromsaid vaporizer means; condenser means connected to said water vaportransfer means for condensing said water vapor to form distilled waterwhich is free of solid contaminants; and distillate transfer meansconnected to said condenser means for withdrawing condensed water fromsaid condenser means; and a heating grid, said heating grid comprising:a base; a plurality of interconnected grid sections mounted on said baseand oriented horizontally to absorb solar energy incident thereupon; aplurality of channel defining ribs on each of said grid sections fordefining flow channels wherein water being distilled in the distillationapparatus flows across the heating grid; an antifriction coating on saidgrid which prevents the adherence of solid contaminants contained insaid water in said grid while said water is flowing thereacross, saidwater remaining in contact with said grid until the temperature of saidwater reaches a predetermined level due to the heat transferred to saidwater from the sun via said grid.
 2. The heating grid defined in claim1, wherein said grid sections are arranged in quadrants with saidchannels of each quadrant being oriented perpendicular to said channelsof adjacent quadrants.
 3. The heating grid of claim 2, wherein said baseis comprised of reinforced concrete, said grid sections are comprised ofa plastic material, and said base is mounted on a gravel sub-base.